Few-cycle Surface Plasmon Polariton Generation by Rotating Wavefront Pulses

A concept for the efficient generation of surface plasmon polaritons (SPPs) with a duration of very few cycles is presented. The scheme is based on grating coupling and laser pulses with wavefront rotation (WFR), so that the resonance condition for SPP excitation is satisfied only for a time window shorter than the driving pulse. The feasibility and robustness of the technique is investigated by means of simulations with realistic parameters. In optimal conditions, we find that a $29.5$~fs pulse with $800$~nm wavelength can excite a $3.8$~fs SPP ($\sim 1.4$ laser cycles) with a peak field amplitude $2.7$ times the peak value for the laser pulse

Rilevamento geologico e geomorfologico delle aree carsiche della Cordillera de la Sal (Deserto di Atacama, Cile)

La Cordillera de la Sal (Deserto di Atacama, Cile) rappresenta uno dei luoghi più aridi del pianeta Terra. La sua particolare collocazione geografica e stratigrafica rendono quest’area uno dei territori carsici in rocce saline più importanti al mondo, con oltre 40 cavità ad oggi conosciute e la terza grotta più lunga al mondo nel sale (sistema carsico Dario Cressi, oltre 5 km di sviluppo). La tesi presenta i risultati del rilevamento geologico eseguito nel corso della spedizione “Reading the salt caves of Atacama” finanziata dal National Geographic ed organizzata dall’Università di Bologna e dall’associazione La Venta – Esplorazioni Geografiche, nel mese di Marzo 2018. A corredo delle analisi di rilevamento geologico e strutturale in grotta ed in superficie, sono state effettuate indagini di remote sensing ed estrazione di modelli digitali del terreno (DEM), a partire da immagini satellitari ad altissima risoluzione fornite dall'ESA (coppie stereografiche Pleiades). Questa tesi ha permesso la realizzazione di una carta geologica di dettaglio in scala 1:100'000 dell’area di studio e la caratterizzazione geo-strutturale e geomorfologica del fenomeno carsico locale. Sono stati inoltre compiuti studi geomorfologici e morfometrici sulle cavità e sui bacini di drenaggio contribuenti, al fine di delineare gli elementi di controllo sulla speleogenesi. In ultimo, sono state testate le potenzialità di analisi strutturali tramite processing di nuvole di punti da fotogrammetria terrestre in una zona di taglio nel settore meridionale della Cordillera de la Sal. L’estrazione di elementi strutturali tramite il software è stata confrontata con i dati misurati sul terreno al fine di controllarne la validità e delineare potenzialità e limitazioni di questo approccio metodologico

SOCIETÀ SEMPLICE, AMMINISTRATORE ESTRANEO E RAPPORTO COL PATTO LIMITATIVO DELLA RESPONSABILITÀ

Il decreto del Giudice del Registro di Roma porta sulla ribalta un grande classico del diritto delle società di persone, ovvero la possibilità di designare amministratore un soggetto non socio. Nello specifico il tema riemerge con riguardo alla società semplice, ovvero il tipo in cui, a causa della controversa interazione tra patto limitativo della responsabilità (di cui all’art. 2267 comma 1) e posizioni di rappresentanza (soci che hanno agito in nome e per conto della società), maggiori erano le perplessità registrate nel dibattito dottrinale e giurisprudenziale rispetto al quadro apparentemente più nitido in tema di snc e di sas. Il Giudice del Registro di Roma accoglie la tesi più permissiva, ma fissa un preciso paletto ancorando la legittimità della designazione del terzo al mancato inserimento in atto costitutivo del patto limitativo (preservando dunque la responsabilità personale e solidale di tutti i soci, che nel caso di specie sono due società di capitali straniere). Il commento prova a ricostruire i riflessi sullo specifico problema interpretativo dell’evoluzione della disciplina di riferimento, ed in particolare la piena legittimazione della partecipazione di società di capitali in società di persone (2003), la prima novella dell’art. 2257 col Codice della crisi (2019) e la seconda novella col decreto correttivo (2020). Ne scaturisce un quadro ancora offuscato in diversi punti e suscettibile di ulteriori sviluppi

On the Use of Tri-Stereo Pleiades Images for the Morphometric Measurement of Dolines in the Basaltic Plateau of Azrou (Middle Atlas, Morocco)

Hundreds of large and deep collapse dolines dot the surface of the Quaternary basaltic plateau of Azrou, in the Middle Atlas of Morocco. In the absence of detailed topographic maps, the morphometric study of such a large number of features requires the use of remote sensing techniques. We present the processing, extraction, and validation of depth measurements of 89 dolines using tri-stereo Pleiades images acquired in 2018–2019 (the European Space Agency (ESA) © CNES 2018, distributed by Airbus DS). Satellite image-derived DEMs were field-verified using traditional mapping techniques, which showed a very good agreement between field and remote sensing measures. The high resolution of these tri-stereo images allowed to automatically generate accurate morphometric datasets not only regarding the planimetric parameters of the dolines (diameters, contours, orientation of long axes), but also for what concerns their depth and altimetric profiles. Our study demonstrates the potential of using these types of images on rugged morphologies and for the measurement of steep depressions, where traditional remote sensing techniques may be hindered by shadow zones and blind portions. Tri-stereo images might also be suitable for the measurement of deep and steep depressions (skylights and collapses) on Martian and Lunar lava flows, suitable targets for future planetary cave exploration

GRB 110709B in the Induced Gravitational Collapse paradigm

Context: GRB110709B is the first source for which Swift BAT triggered twice, with a time separation of ~10 min. The first emission (Ep. 1) goes from 40s before the 1{\deg} trigger up to 60s after it. The second (Ep. 2) goes from 35s before the 2{\deg} trigger to 100s after it.[...] Within the Induced Gravitational Collapse (IGC) model, we assume the progenitor to be a close binary system composed of a core of an evolved star and a Neutron Star (NS). The evolved star explodes as a Supernova (SN) and ejects material that is partially accreted by the NS. We identify this process with Ep. 1. The accretion process brings the NS over its critical mass, thus gravitationally collapsing to a BH. This process leads to the GRB emission, Ep. 2.[...] Aims: We analyze the spectra and time variability of Ep. 1 and 2 and compute the relevant parameters of the binary progenitor[...] in the IGC paradigm. Methods: We perform a time-resolved spectral analysis of Ep. 1 with a blackbody (BB) plus a power-law (PL) spectral model. We analyze Ep. 2 within the Fireshell model, identifying the Proper-GRB (P-GRB) and simulating the light curve and spectrum. We establish the redshift to be z=0.75 [...]. Results: We find for Ep. 1 a BB temperature following a broken PL with time, with the PL slopes at early and late times \alpha=0 and \beta=-4+/-2, respectively, and a break at t=41.21s. The total energy of Ep. 1 and 2 are E_{iso}^1=1.42x10^{53}erg and E_{iso}^2=2.43x10^{52}erg, respectively. We find at transparency a Lorentz factor \Gamma~173, laboratory radius of 6.04x10^{13}cm, P-GRB observed temperature kT_{P-GRB}=12.36keV, baryon load B=0.0057 and P-GRB energy E_{P-GRB}=3.44x10^{50}erg. [...] Conclusions: We interpret GRB110709B as a member of the IGC sources, together with GRB970828, GRB090618 and GRB101023. The XRT data during Ep. 2 offers an unprecedented tool for improving the diagnostic of GRBs emission.Comment: 12 pages, 17 figures, to appear on A&

A family of consistent normally distributed tests for Poissonity

A consistent test based on the probability generating function is proposed for assessing Poissonity against a wide class of count distributions, which includes some of the most frequently adopted alternatives to the Poisson distribution. The statistic, in addition to have an intuitive and simple form, is asymptotically normally distributed, allowing a straightforward implementation of the test. The finite sample properties of the test are investigated by means of an extensive simulation study. The test shows a satisfactory behaviour compared to other tests with known limit distribution

Evaluation of biomechanical effects of interocclusal surfaces on the mandible

ABSTRACT Introduction: Only few studies in the literature employ a mathematical model in the evaluation of the stress which follows the application of loads and constraints onto the mandible. Therefore, new approaches are needed so that the study of this phenomenon can rely less on the clinical hypothesis and experience of the operator, while taking advantage of the many benefits that virtual representations and mathematical calculations present. Aim of the study is to determine, by means of the finite element method (FEM), the stress produced onto the mandible as a result of the application of a force on itself, in association or not to the perioral musculature and according to the dental support given by the positioning of an interocclusal surface at three different levels: mesial, intermediate and distal. Aim: The aim is to allow a more objective evaluation of this phenomenon, its absolute repeatability, as well as to acquire important clinical informations concerning the role of orthodontic and gnathologic appliances. Materials and methods: Starting from a 1:1 scale model of the mandible (human adult male), a virtual three - dimensional (3D) representation was first obtained thanks to a dedicate software; it was then imported into a second software in order to permit the discretization into finite elements of the virtual model and the attribution of its mechanical properties. Finally, thanks to a specific software, it was possible to simulate the presence of load and constraints and to evaluate the stress status by using pseudo - colors. Results: The stress generated following the application of a force onto the mandible, undergoes significant variations in relation to the dental support and the presence or absence of the perioral musculature. Conclusions: Following the results of our research, we consider FEM as a valid and interesting method for this purpose, however additional FEM conducted studies are necessary in order to assess this phenomenon in more detail and determine the role of the perioral musculature as well as the possible clinical implications

Design-based spatial interpolation with data driven selection of the smoothing parameter

In the inverse distance weighting interpolation the interpolated, value is a weighted mean of the sampled values, with weights decreasing with the distances. The most widely adopted class of distance functions is the class of negative powers of order α and the appropriate choice of the smoothing parameter α is a crucial issue. In this paper, we give sufficient conditions for the design-based consistency of the inverse distance weighting interpolator when α is selected by cross-validation techniques, and a pseudo-population bootstrap approach is introduced to estimate the accuracy of the resulting interpolator. A simulation study is performed to empirically confirm the theoritical findings and to investigate the finite-sample properties of the interpolator obtained using leave-one-out cross-validation. Moreover, a comparison with the nearest neighbor interpolator, which is the limiting case for α = ∞, is performed. Finally, the estimation of the surface of the Shannon diversity index of tree diameter at breast height in the experimental watershed of Bonis forest (Southern Italy) is described

Criteri di buona governance in Leader: l\u2019autovalutazione dei Gruppi di Azione Locale

l principale obiettivo di questo lavoro \ue8 proporre una metodologia per l\u2019autovalutazione della capacit\ue0 del Gruppi di Azione Locale (Gal) di elaborare e gestire una strategia locale Leader secondo principi di buona governance. L\u2019approccio proposto, inizialmente sviluppato e testato in via preliminare con tecniche di ricerca qualitativa \ue8 qui perfezionato e integrato con il Common Assessment Framework (Caf), un modello di autovalutazione in uso da tempo presso organizzazioni pubbliche in Europa. Il sistema proposto si basa su un set d\u2019indicatori specifici di prestazione (performance) e di percezione del Gal capaci di correlare i principali elementi di una buona governance alle specificit\ue0 dell\u2019approccio Leader. Questo strumento pu\uf2 contribuire a migliorare l\u2019attivit\ue0 di monitoraggio gestionale e indirizzare criticamente le attivit\ue0 del Gal

Goodness-of-fit test for count distributions with finite second moment

A goodness-of-fit test for one-parameter count distributions with finite second moment is proposed. The test statistic is derived from the $L_1$-distance of a function of the probability generating function of the model under the null hypothesis and that of the random variable actually generating data, when the latter belongs to a suitable wide class of alternatives. The test statistic has a rather simple form and it is asymptotically normally distributed under the null hypothesis, allowing a straightforward implementation of the test. Moreover, the test is consistent for alternative distributions belonging to the class, but also for all the alternative distributions whose probability of zero is different from that under the null hypothesis. Thus, the use of the test is proposed and investigated also for alternatives not in the class. The finite-sample properties of the test are assessed by means of an extensive simulation study